Resilient cradle for boat trailers



2 Sheets-Sheet 2 N. E. COLE June 19, 1962 RESILIENT CRADLE FOR BOATTRAILERS Filed July 2, 1959 E a m m E m w QN S L E N w Y B @N E JJWMHHHHHHHHHHHH "X I I I I I I I QN ON 0N PN ATTORNEY United StatesPatent C) 3,039,629 RESILIENT CRADLE FQR BOAT TRAJLERS Nelson E. Cole,Reading, Pa., assignor to Dana Corporation, Toledo, Ohio, a corporationof Virginia Filed July 2, 1959, Ser. No. 824,589 6 Claims. ((11. 214-84}This invention relates to improvements in boat trailers in general andis particularly directed to improvements in boat trailers equipped withcradles which are capable of providing firm, resilient supports for aboat hull, and further which are readily deformable under load so as toconform with a variety of different shaped hulls.

A primary object of this invention is to provide a boat trailer with aplurality of cradles. The cradles are composed of a mounting shaft and apair of relatively large fluid pressure filled bags which are freelyrotatable on the mounting shafts. These cradles are supported by theframe of a conventional boat trailer and are used as a loading,unloading and transporting medium of boats and further will conform todifferent sizes and shapes of boat hulls without adjustment thereof.

A further object of the invention is to provide a cradle adapted tosupport a boat hull thereon with the forces on the cradle caused by theweight of the boat hull being mainly tensile in nature rather thancompressive whereby the cradle is not compacted into a harder mass butremains substantially as resilient under load as it was prior to theapplication of the load.

Further objects and advantages will become apparent upon reading thefollowing specification together with the accompanying drawings whichform a part hereof.

In the drawings:

FIG. 1 is a perspective view of a boat trailer equipped with theresilient cradles of this invention.

FIG. 2 is a side elevation view of the resilient cradle partly insection.

The improved cradle of this invention embodies a struc tural form whichpermits it to support a boat hull resiliently over a broad area so thatwhen the contacting surfaces of the cradle are placed under load, theforces acting thereon are more tensile in nature rather than purelycompressive as has heretofore been the custom. These resilient fluidpressure filled bags when subjected to the load of a boat hull deformunder the load so as to conform to different sizes and shapes of boathulls.

Prior art boat trailers have been made from a plurality of supportingsurfaces in the form of rollers which are usually longitudinally alignedand laterally spaced so as to provide points of support fora boat hullplaced thereon. These rollers are particularly advantageous for loading,unloading and carrying a boat. The rollers of these prior art boattrailers have utilized resilient material for the actual contactingareas thereof because it is necessary that the rollers be yieldable toprevent damage to the boat hull being transported thereon. The resilientmaterial of these rollers has customarily been rubber or rubberlikematerial but the construction has been of a type wherein the resistanceto deformation under load progressively increases as the load is appliedwith the result that the rollers become compacted and hard due to thecompressive forces thereon. Various forms of boat cradles exist in theprior art such as those made from a resilient material sleeved over ashaft. When cradles such as these are used to support a boat hull,however, they are loaded in compression with the result that theresilient material of the rolls therein is compacted, increasing theresistance to deformation and this increased deformation thereof causesa relatively hard support area which results in a high number of damagedboat hulls, especially those hulls made of plastic material. Thisresults in either the boat hulls being reworked or scrapped. A furtherassaszs Patented June 19, 1962 objection to boat trailers of this typeis that the support areas are relatively small, resulting insubstantially a line contact of high unit pressure loading.

As shown in FIG. 1, a boat trailer, indicated as a whole by thereference numeral 10, is equipped with three cradle assemblies 11according to this invention and includes, a conventional trailer frame12 mounted on an axle 13 for supporting a pair of ground wheels 14having a centrally disposed tongue 15 extending at right angles to theaxle 13 and suitable attaching means, not shown, on the end of thetongue 15 for removable attachment to avehicle. The plurality of cradlemechanisms '11 are laterally supported and longitudinally spaced uponthe frame 12 of the trailer 10, and are adapted as supports for thebottom surface of a boat, at points intermediate the bow and stem.Longitudinally spaced groups of holes 16 are provided at differentpoints along the side rails 17 and 18 of the frame 12 for positioningthe cradles 11 relative to each other and for adding or subtractingcradles from the trailer 10 as requirements dictate. Heretofore,different sizes of cradles were required for various sizes and shapes ofboat hulls. This is expensive and requires the changing of cradles fordifferent size boat hulls proposed to be carried.

Referring to FIG. 2, the boat cradle 11 consists of a mounting member orshaft 19 adapted for attachment to the side rails 17 and 18 of the frame12 of a boat trailer 10 of the type mentioned above. It is understoodthat various other types of boat trailers may be employed, for instance,a pole type trailer wherein the shafts 19 are adapted to be supported attheir centers instead of their ends as shown.

The mounting shaft 19 is suitably secured or joined to the frame 12, asby cap screws 20 at its opposed ends. A pair of fluid pressure bags 21are rotatably mounted on, intermediate the ends of the mounting shaft 19and are disposed in spaced relation thereon. It will be noted that themounting shaft 19 not only supports the fluid pressure bags 21 forrotation relative thereto, but also serves as the main cross-member ofthe trailer frame 12. A boat 22 is fragmentarily shown disposed betweenthe fluid pressure bags 21 showing the bags 21 coinciding with theparticular angular inclination of the bottom of the boat 22.

The fluid pressure bags 21 are made of a rubber impregnated fabric orany other suitable material and are mounted on a hollow shaft 23 whichis sleeved over the mounting shaft 19. More particularly, the fluidpressure bag 21 comprises a resilient, wheel-like body 24 which,although preferably an integral structure, as shown, may be formed froman outer annular tread and an inner concentric annular hub connectedtogether as is common in the art. The bag 21 is secured to the hollowshaft 23 by flanges 25 and 26 so that one half of the bag 21 has theappearance of a doughnut in cross-section. The

- flange '25 is fixedly secured tothe hollow shaft 23 as by welding. Theflange 26 is detachedly secured to the hollow shaft 23 for placing thebody 24 thereon. An air valve 27 is provided in the body 24 forcontrolling the amount of pressure therein. Annular adjustable rings 28are disposed adjacent each end of the shaft 23 for positioning the bags21 relative to each other on the mounting shaft 19. Bushings 29 and 30are disposed between the hollow shaft 23 and mounting shaft '19 ateither end of the bag 21. It is to be noted that the longitudinal lengthof the air bag 21 is longer than the relatively large diameter thereof,thereby providing a large contact area for supporting a boat hull. Thebody 24 being made of a resilient material and filled with air pressureof a relatively low value, then results in a structure which will firmlyand resiliently support a load without damage thereto and will adaptitself to various shapes of boat hulls without adjustment. This type ofstructure is not subjected to the compacting which would result frompure compression loading, and consequently, the bag 21 does not becomehard under loads but remains resilient and, therefore, can absorb shockloads transmitted from a boat being transported over rough roads withoutdamage there- The fluid pressure bags 21 as shown in FIG. 2 representthe deformation of the body 24 whensubjected to forces caused by a boathull which is generally U- or V-shaped. In this instance the tread 31 ofthe body 24 is inclined downwardly at one end while the free edge or web32 is deflected and somewhat buckled at its outer portion. A U- orV-shaped boat hull will tend 'to wrinkle the web 32 as shown in FIG. 2,and the tread 31 of the body 24 will be stressed about its juncturepoint 33 so as to lie flat along the surface of the boat hull 22. Theboat hull 22 will then be supported both vertically and laterally mainlyby the resilience of the tread 31 which is stressed and deflectedinwardly toward the hollow shaft 23.

It will now be apparent that the novel boat cradle here in disclosedprovides both lateral and vertical supports for a boat hull, the fluidpressure bags 21 readily conforming substantially to the configurationof the boat being carried and the resiliency thereof being unimpaireddue to the fact that the bag 21 is not compacted under pressure exertedby the boat hull being carried. These cradles then will replace thehighload, small area support points conventionally provided by the hardrubber rollers as is customarily used, with a large low pressure areaclosely fitting the hull shape.

It will be obvious that various changes in the details which have beenherein described and illustrated in order to explain the nature of thisinvention, may be made by those skilled in the art within the principleand scope of the invention as expressed in the appended claims.

What is claimed is:

1. A boat trailer comprising the combination of a subing contour engagesaid rollers during loading and un- Istantially longitudinally extendingtrailer frame with suitable wheel and axle means for the mobilitythereof, means on said frame for attachment to a drawing vehicle, amounting shaft located transversely to the longitudinal axis of saidframe and being carried by the frame, a pair of resilient fluid pressurefilled rollers carried in spaced apart relation by said shaft toaccommodate the keel of a boat therebetween, said rollers having ahollow baglike configuration with the axial length of each roller beingsubstantially greater than the radius thereof so that when boat hulls ofvarious size and constantly varyloading, the rollers will conform to theshape of the boat hulls and give both vertical and lateral supportthereto over a large area and aid in centeringthe boat on the trailer,said rollers being susceptible to further resilient deformation tocushion the boat during transit of the trailer.

2. The boat trailer as defined in claim 1 wherein said rollers arerotatably mounted on. said mounting shaft.

3. The boat trailer as defined in claim 1 wherein said mounting shaft isadjustably secured to said frame.

4. The boat trailer as defined in claim 1 wherein said frame comprisesspaced apart side rails to which the mounting shaft is secured.

'5. The boat trailer as defined in claim 1 wherein said rollers areadjustably positioned on said mounting shaft.

6. A boat trailer comprising the combination of a sub stantiallylongitudinally extending trailer frame with suitable wheel and axlemeans for the mobility thereof, means on said frame for attachment to adrawing vehicle, a mounting shaft located transversely to thelongitudinal axis of said frame and being carried by the frame, a pairof resilient fluid pressure filled roller means carried in spaced apartrelation by said shaft to accommodate the keel of a boat therebetween,each of said roller means having a total axial length substantiallygreater than the radius thereof so that when boat hulls of various sizeand constantly varying contour engage said roller means during loadingand unloading, the roller means will conform to the shape of the boathulls and give both vertical and lateral support thereto over a largearea and aid in centering the boat on the trailer, said roller meansbeing susceptible to further resilient deformation to cushion the boatduring transit of the trailer.

References Cited in the file of this patent UNITED STATES PATENTS710,936 Bacon Oct. 14, 1902 729,68'2- Selleck June 2, 1903 1,736,130 DeCloud Nov. 19, 1929 I 2,007,910 Stephens July.9, 1935 2,190,905 WelchFeb. 20, 1940 2,613,788 McLaughlin Oct. v14, 1952 2,716,499 Grant -QAug. 30, 1955 2,740,543 Moundsdon Apr. '3, 1956 2,860,792 Nelson et al.-4- Nov. 18, 1958 2,910,835 Timothy Nov. 3,1959

